Fix grafast link

Author: jemgillam

src/pages/index.mdx

@@ -43,7 +43,7 @@ Enables greater performance and efficiency via deeper integration into your exis
 
 <div class='df flex-row justify-center' style={{height: '3rem'}}>
 <div class='ph2 df flex-column justify-center'>
-<a class='button--outline' href='https://graphile.org'><span class='fas fa-bolt' /> Get Started</a>{ ' '}
+<a class='button--outline' href='https://grafast.org'><span class='fas fa-bolt' /> Get Started</a>{ ' '}
 </div>
 </div>
 </MarketingProduct>